1. Field of the Invention
The present invention relates to a method of polishing a semiconductor wafer being retained by a template.
2. Description of Prior Art
To enhance working efficiency and prevent environmental pollution, semiconductor manufacturing processes have been increasingly utilized to polish a semiconductor wafer retained by a template without using wax.
The process of polishing a semiconductor wafer by the aid of a template is shown in FIG. 5. As shown in FIG. 5, a semiconductor wafer 10 is retained by a template 1a, and an abrasive cloth 5 secured on a base 4 is pressed in to contact with the semiconductor wafer 10 to facilitate polishing. To take the machining allowance of semiconductor wafers into consideration, the thickness of the template 1a is made 100 .mu.m thinner than that of the semiconductor wafer 10 to allow the semiconductor wafer 10 to be polished entirely.
Due to the enhancement in techniques of lapping and plane grinding, the preparation of semiconductor wafers with high flatness has recently resorted to the procedure of polishing. However, in the above-described conventional polishing operation, as shown in FIG. 4, waviness 12b will occur on the polished surface 11b and the outer periphery of the semiconductor wafer 10 will become steeply inclined. Therefore, the TTV of the semiconductor wafer 10 will become worse.